Formula reference

Formulas work out a value from data the workflow already has. They’re used in a Calculation step, in any value set to Calc, inside {{ }} in text and JSON, and in branch rules.

Formulas use CEL, with a few changes that make them forgiving:

• A field that doesn’t exist reads as empty instead of failing.
• Empty text, 0, empty lists and empty values count as false.
• Every number is a decimal, so 3 and 2.5 mix freely.

Type {{ or press Ctrl+Space in a formula to choose an input, variable or earlier result. In a Calc value the reference goes in without braces, like input.quantity.

Sample data

Every example on this page runs against this data. The build checks each one against the real formula engine, so the results are exactly what a workflow gets.

{
  "input": {
    "name": "Ada Lovelace",
    "email": " Ada@Example.com ",
    "quantity": 3,
    "price": 2.5,
    "tags": [
      "vip",
      "beta"
    ],
    "company": ""
  },
  "nodes": {
    "lookup": {
      "output": {
        "found": true,
        "row": {
          "Status": "Active",
          "Plan": "Pro"
        }
      }
    }
  },
  "total": 10
}

input holds the workflow’s inputs. nodes.<step>.output holds an earlier step’s results, and workflow variables are read by name, like total.

Operators

Operator	Meaning	Example	Result
+	Add two numbers, or join two pieces of text	input.quantity + 1	4
-	Subtract, or make a number negative	total - input.quantity	7
*	Multiply	input.quantity * input.price	7.5
/	Divide. The result can be a decimal	10 / 4	2.5
==	Equal to	input.name == "Ada Lovelace"	true
!=	Not equal to	input.quantity != 3	false
<	Less than	input.price < 3	true
<=	Less than or equal to	input.price <= 2.5	true
>	Greater than	input.quantity > 2	true
>=	Greater than or equal to	input.quantity >= 5	false
&&	Both sides are true	input.quantity > 2 && input.price < 3	true
||	Either side is true	input.quantity > 5 || nodes.lookup.output.found	true
!	Not. Empty text, zero and empty values count as false	!input.company	true
? :	If the first part is true, the second, otherwise the third	input.company ? input.company : "No company"	"No company"
in	The list contains the value	"vip" in input.tags	true
.	A field inside a value	nodes.lookup.output.row.Status	"Active"
[ ]	An item in a list, counting from 0	input.tags[0]	"vip"

Use brackets to group parts: (input.quantity + 1) * input.price.

Functions

Function	What it gives	Example	Result
has()	Whether a field exists. Takes one field path	has(input.email)	true
size()	Characters in text, items in a list, or fields in an object	size(input.tags)	2
string()	Turn a value into text	string(input.quantity) + " items"	"3 items"
double()	Turn text into a number	double("2.5") * 2	5

Methods

Call a method on a value with a dot.

Method	What it gives	Example	Result
.size()	Characters in text, or items in a list	input.name.size()	12
.contains()	Whether text contains other text. Case-sensitive	input.name.contains("Love")	true
.startsWith()	Whether text starts with other text. Case-sensitive	input.name.startsWith("Ada")	true
.endsWith()	Whether text ends with other text. Case-sensitive	input.name.endsWith("lace")	true
.lowerAscii()	Text in lower case. Changes A to Z only	input.email.trim().lowerAscii()	"ada@example.com"
.upperAscii()	Text in upper case. Changes a to z only	input.name.upperAscii()	"ADA LOVELACE"
.trim()	Text without spaces at the start and end	input.email.trim()	"Ada@Example.com"
.join()	A list of text joined into one piece of text, with an optional separator	input.tags.join(", ")	"vip, beta"

Methods can be chained: input.email.trim().lowerAscii().

Missing fields

input.missing gives null.

Check for a field with has(), or supply a fallback with ? :.

Errors

A formula that can’t run fails its step. The step’s error names one of these codes.

Error code	What happened	Example that fails
runtime-workflow.expression.invalid	The formula isn’t valid: a typo, an unsupported operator or function, or it’s too long	input.quantity % 2
runtime-workflow.expression.division_by_zero	Something was divided by zero	total / 0
runtime-workflow.expression.type_mismatch	An operator got values it can’t use, like text times a number. Use string() or double() to convert first	input.name + 1
runtime-workflow.expression.number_out_of_range	A number got too large to store	1e308 * 10

Text and numbers never convert by themselves. Use string() to turn a number into text, and double() to turn text into a number.

Limits

A formula can be up to 1,024 characters long.

There are no loops, regular expressions or date functions.